Configuration: may be collect resource owner types automatically?

[gassan]

HWIOAuthBundle/src/DependencyInjection/Configuration.php

Line 97 in a25e4a7

'yahoo',

'yahoo' extending GenericOAuth2ResourceOwner, so it should belong to 'oauth2' array.
I think, Configuration::$resrouceOwners array can be calculated automatically with scandir of OAuth/ResourceOwners folder. As well this array can be used to register hwi_oauth.resource_owner.*.class parameters.
I am almost done with review, will send a PR shortly.

Benefits:
We can get oauth type from ResourceOwner::TYPE constant or derive it from class name without ResourceOwner suffix (snake_case).
So we do not need to set type and class no need to set type and class simultaneously.
OAuth[12]ResourceOwner final classes should be created (fixes #1870)
We can get all app classes that implemented ResourceOwnerInterface and register them in the same way.
...

[stloyd]

Closing as #1872 was just merged 🚀